This invention relates to an audio signal fader control system and an operating method therefor.
Audio signal mixing is conventionally performed using an audio mixing desk which may have analog audio mixers or be digitally operated. In an analog audio mixer the audio signal is modified between input and output of the mixer by an editor applying gain and attenuation to the audio signal using slider fader controls.
In a digital system, the signal is processed with a digital signal processor (DSP) and values for gain and attenuation from fader controls are generated using an analog to digital converter (ADC) which communicates with the DSP.
The values generated by either the analog or the digital system are usually stored and later played back. If a digital system is used then digital position values are converted back to a voltage using a digital to analog converter (DAC), which voltage is used to drive a motorized fader control.
The process of driving a motorized fader control from stored or computed audio level control values is called "dynamic automation". When playing back the stored audio, the editor may modify the audio signal by revising the motorized fader control position. In this respect it is usual for the motorized fader control to have the motor drive disabled when the control is touched by an editor so as to avoid the motor being burned out. When the editor modifies the fader control position to modify the audio during playback mode, the new fader position is stored.
A discussion of digital audio and digital fader controls can be found in "The Art of Digital Audio", 2nd Edition by John Watkinson at Section 2.8, page 48, published by Focal Press, ISBN 0-240-51320-7.
A problem with motorized fader controls is that they have inertia and that it takes a period of time for the fader to arrive at a new desired position. Furthermore, the fader control is usually located in a control console which is connected over a network to a host computer system. The network introduces communication delays which again lead to a time error in the motorized fader control arriving at a desired position.
The object of this invention is to provide dynamic automation with the capability of moving the motorized fader control to be at a desired position at a required time.